Modern cellular communication networks typically support numerous user devices, all of which are competing for limited communication resources. Communication service providers face the constant challenge of serving their many customers, many of whose activities consume significant resources, with the infrastructure and communication spectrum available to them. Adding infrastructure to meet increasing demand is costly. In addition, if the spectrum required by the demands of users is greater than the spectrum available to meet those demands, increasing infrastructure will not meet those demands.
To avoid the costs of adding infrastructure, and to help insure that the available spectrum will meet the demands placed upon it, service providers seek to use their available resources as efficiently as possible. One important aspect of efficient resource use is adapting signals to the devices to which they are being transmitted.
One mechanism for efficient use of resources is carrier aggregation. Many base stations may employ multiple carriers to provide coverage to a sector. For example, a base station may employ a 700 MHz carrier and a 2 GHz carrier, and a base station may be configured to transmit to a user device using both carriers. In addition, a user device may be within range of multiple base stations and can connect to a single carrier, multiple carriers from a single base station, or carriers from multiple base stations, in order to achieve a better peak rates and capacity. In third generation partnership project (3GPP) and 3GPP long term evolution (3GPP-LTE) networks, base stations may be implemented as eNodeBs (eNBs) and user devices may be referred to as user equipments (UEs).
Another mechanism for efficient use of resources employs beamforming, of which one useful approach is elevation beamforming. A base station may employ an antenna array, and signal components provided to each element of the array may be chosen so as to optimize signal gain for a particular UE.